Brownells 75th Anniversary - A Shooting Heritage

RBF (Reinforced Buffer retainer, Forward Controls) is a strengthened AR buffer retainer machined with Swiss machines from 17-4 stainless steel bar stock, and heat treated to H900 hardness.  RBF features a reinforced tip that is 10% larger (0.102) than TDP spec (0.093).  FCD didn’t want RBF to be timed (as the case with a rectangular tip), so RBF retains the TDP buffer retainer's versatile round tip and is installed per TM instructions.  10% is as much as we could increase before encountering receiver extension timing incompatibilities.

RBF is compatible with AR15/M16 mil-spec rifle and carbine receiver extensions, as well as Vltor A5 system receiver extensions.

  • 17-4 stainless steel
  • Heat treated
  • AR15 and 308 AR compatible buffer retainer
  • 10% larger diameter tip


  • Always wear eye protection while handling springs under pressure, spring loaded pins and detents.
  • RBF isn't a fix for out of spec lowers with incorrectly positioned buffer retainer hole.  If you detect excessive wear marks on the buffer's front face, it's advisable to warranty exchange your lower receiver.
  • Receiver extensions (REs) timing on the receiver can vary.  While the an RE can rotate past dead center (with the RE covering and retaining the buffer retainer) by 45 degrees or more on one receiver, it might only be able to do 15 degrees or less on another.  Also, different REs have different timing values.

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